Hi guys, I'm new to this forum, and I'm not even sure if I'm posting this in the right place...But here goes nothing

The back story:
My grandfather adopted this german shepherd, Holly when she was a puppy about 3 or 4 years ago. He was in his mid 80s, so as you can imagine, she didn't get the training or exercise she needed. She wasn't walked, wasn't introduced to new people, and has never really been anywhere other than a small grassless and poo-covered yard. My grandfather is in the last stages of esophageal/lung cancer, and will be unfortunately leaving us very soon. I asked him if I could take care of Holly for him, as I have always been an avid dog lover, and she seemed to take interest in me. So 2 days ago, I made the 5 hour drive back from the hospital, and brought Holly to our home.

I live with my boyfriend, and right off the bat, she growled at him and runs from him when he tries to pet her or talk to her. I know that her new life here is a complete 180* from where she came from and what she's used to. I'm the only person she knows, and she is very comfortable with me. I'm being very dedicated to teach her commands, sit, lay, load up, heel, come, and things are going well considering the amount of time she's had. I am very concerned with her attitude towards my boyfriend though, and am not sure how to improve the situation. I know she's probably still stressed, and misses her companion (a 6 year old rotweiler), but she is having a hard time trusting my boyfried, and although she is very gentle, he is uncomfortable and thinks she will bite him.

Any type of help or tips or ANYTHING really would help. Thanks so much.